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ISO/IEC JTC1/SC 29/WG11/N 6269 Date: 2003-12-16

ISO/IEC PDTR 21000-1

ISO/IEC JTC1/SC 29/WG 11

Secretariat: JISC

Information technology — Multimedia framework (MPEG-21) — Part 1: Vision,Technology and Strategy

Technologies de l'information — Cadre multimédia (MPEG-21) — Partie 1: Vision, Technologie et Stratégie

Document type: Technical ReportDocument subtype: Document stage: (20) PreparatoryDocument language: E


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Contents Page

Foreword.................................................................................................................................................. vExecutive Summary............................................................................................................................... viiIntroduction........................................................................................................................................... viii1 Scope........................................................................................................................................... 12 Terms and Definitions................................................................................................................13 Symbols and Abbreviated terms...............................................................................................2Structure of the Technical Report..........................................................................................................43.1 Problem Statement.....................................................................................................................53.2 Solution Statement.....................................................................................................................53.3 Normative Implications...............................................................................................................53.4 Conformance and Reference Software.....................................................................................63.5 Description of a Multimedia Framework Architecture.............................................................63.5.1 Digital Items................................................................................................................................. 63.5.2 Users............................................................................................................................................ 73.6 Example MPEG-21 Use Case.....................................................................................................73.6.1 Introduction................................................................................................................................. 73.7 Enabling MPEG-21 Technologies..............................................................................................83.8 Activities Related to the Multimedia Framework......................................................................94 About ISO/IEC 21000-1:2001....................................................................................................105 Overview of the MPEG-21 Parts...............................................................................................105.1 Part 1 – Vision, Technologies and Strategy............................................................................115.2 Part 2 – Digital Item Declaration (DID).....................................................................................115.3 Part 3 – Digital Item Identification (DII)....................................................................................115.4 Part 4 – Intellectual Property Management and Protection (IPMP).......................................125.5 Part 5 – Rights Expression Language (REL)..........................................................................125.6 Part 6 – Rights Data Dictionary (RDD).....................................................................................135.7 Part 7 – Digital Item Adaptation (DIA)......................................................................................145.8 Part 8 – Reference Software.....................................................................................................145.9 Part 9 – File Format................................................................................................................... 145.10 Part 10 – Digital Item Processing (DIP)...................................................................................155.11 Part 11 – Evaluation Methods for Persistent Association Technologies.............................155.12 Part 12 – Test Bed for MPEG-21 Resource Delivery..............................................................155.13 Part 13 – Scalable Video Coding..............................................................................................156 MPEG-21 Achievements...........................................................................................................166.1 Introduction............................................................................................................................... 166.2 ISO/IEC 21000-2: Digital Item Declaration (DID).....................................................................166.2.1 Goal............................................................................................................................................ 166.2.2 Rationale.................................................................................................................................... 166.2.3 Key concepts and basic approach..........................................................................................166.3 ISO/IEC 21000-3: Digital Item Identification (DII)....................................................................206.3.1 Goal............................................................................................................................................ 206.3.2 Rationale.................................................................................................................................... 206.3.3 Key concepts and basic approach..........................................................................................206.4 ISO/IEC 21000-5: Rights Expression Language (REL)...........................................................206.4.1 Goal............................................................................................................................................ 206.4.2 Rationale.................................................................................................................................... 206.4.3 Key concepts and basic approach..........................................................................................206.5 ISO/IEC 21000-6: Rights Data Dictionary (RDD).....................................................................22

© ISO/IEC 2003 — All rights reserved III


6.5.1 Goal............................................................................................................................................ 226.5.2 Rationale.................................................................................................................................... 226.5.3 Key concepts............................................................................................................................. 227 Highlights of the MPEG-21 Parts under Development...........................................................237.1 ISO/IEC 21000-7: Digital Item Adaptation (DIA)......................................................................237.1.1 Goal............................................................................................................................................ 237.1.2 Rationale.................................................................................................................................... 247.1.3 Key concepts and basic approach..........................................................................................247.2 ISO/IEC 21000-10: Digital Item Processing.............................................................................257.2.1 Goal............................................................................................................................................ 257.2.2 Rationale.................................................................................................................................... 257.2.3 Key Concepts............................................................................................................................ 257.3 ISO/IEC 21000-11: Evaluation Methods for Persistent Association Technologies..............267.3.1 Goal............................................................................................................................................ 267.3.2 Rationale.................................................................................................................................... 267.3.3 Key concepts............................................................................................................................. 277.4 ISO/IEC 21000-12: Test Bed for MPEG-21 Resource Delivery...............................................287.4.1 Goal............................................................................................................................................ 287.4.2 Rationale.................................................................................................................................... 287.4.3 Key Concepts............................................................................................................................ 28Annex A (informative) List of Activities Related to the Multimedia Framework................................30Bibliography............................................................................................................................................. 38

IV © ISO/IEC 2003 — All rights reserved


Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.

In exceptional circumstances, when a technical committee has collected data of a different kind from that which is normally published as an International Standard (“state of the art”, for example), it may decide by a simple majority vote of its participating members to publish a Technical Report. A Technical Report is entirely informative in nature and does not have to be reviewed until the data it provides are considered to be no longer valid or useful.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.

ISO/IEC TR 21000-1 was prepared by Technical Committee ISO/IEC/TC JTC1, Information Technologt, Subcommittee SC 29, Coding of of audio, picture, multimedia and hypermedia information.

This second edition cancels and replaces the first edition of which has been technically revised.

ISO/IEC TR 21000 consists of the following parts, under the general title Information technology — Multimedia framework (MPEG-21):

Part 1: Vision, Technologies and Strategy

Part 2: Digital Item Declaration

Part 3: Digital Item Identification

Part 4: Intellectual Property Management and Protection

Part 5: Rights Expression Language

Part 6: Rights Data Dictionary

Part 7: Digital Item Adaptation

Part 8: Reference Software

Part 9: File Format

Part 10: Digital Item Processing

Part 11: Evaluation Methods for Persistent Association Technologies

Part 12: Test Bed for MPEG-21 Resource Delivery

© ISO/IEC 2003 — All rights reserved V


Part 13: Scalable Video Coding

Part 14: Conformance Testing

Note: other parts may be added when needed.

VI © ISO/IEC 2003 — All rights reserved


Executive Summary

Currently, multimedia technology provides content creators and consumers with a myriad of coding, access and distribution possibilities. At the same time, communication infrastructure is being put into place to enable access to information and multimedia services from almost anywhere at anytime. Still, no global end-to-end solutions exist allowing all different user communities to interact in an interoperable way. This lack of interoperable (and thus standardized) solutions is stalling the deployment of advanced multimedia packaging and distribution applications although most of the individual technologies are indeed already present.

This motivated MPEG (ISO/IEC JTC1 SC29 WG11) in June 2000 to start to work on the definition of enabling normative technology for the multimedia applications of the 21st century: MPEG-21 “Multimedia Framework”. MPEG-21’s approach is to define a framework to support transactions that are interoperable and highly automated, specifically taking into account Intellectual Property Management and Protection requirements and targeting multimedia access and delivery using heterogeneous networks and terminals. This significant progress that was made in developing MPEG-21 since the publication of first edition of this Technical Report in 2001 (ISO/IEC 21000-1:2001) has led to this updated version.

Based on the above observations, MPEG-21 aims at defining a normative albeit open framework for multimedia delivery and consumption for use by all the players in the delivery and consumption chain. This open framework will provide content creators and service providers with equal opportunities in the MPEG-21 enabled open market. This will also be to the benefit of the content consumer providing them access to a large variety of content in an interoperable manner.

The MPEG-21 vision can thus be summarized as follows: to define a multimedia framework to enable transparent and augmented use of multimedia resources across a wide range of networks and devices used by different communities.

MPEG-21 identifies and defines the normative technologies needed to support the multimedia delivery chain as described above as well as the relationships between and the operations supported by them. Within the parts of MPEG-21, these elements are elaborated by defining the syntax and semantics of their characteristics, such as interfaces to the elements.

Part 1 of MPEG-21 (ISO/IEC 21000-1) provides:

a) A vision for a multimedia framework to enable transparent and augmented use of multimedia resources across a wide range of networks and devices to meet the needs of all Users1)

b) A method to facilitate the integration of components and standards in order to harmonise technologies for the creation, management, manipulation, transport, distribution and consumption of content;

c) A strategy for achieving a multimedia framework by the development of specifications and standards based on well-defined functional requirement through collaboration with other bodies.

1) A User is any entity that interacts in the MPEG-21 environment or makes use of a Digital Item (all capitalised terms are used as defined in Clause 2)

© ISO/IEC 2003 — All rights reserved VII


Introduction

End users’ appetite for content and the accessibility of information is increasing at an incredible pace. Access devices, with a myriad set of different terminal and network capabilities, are making their way into end users’ lives. Additionally, these access devices are used in different locations and environments. Their users, however, are currently not given tools to deal efficiently with all the intricacies of this new multimedia usage environment.

Enabling “ease of use” is becoming increasingly important as individuals are producing more and more digital media for their personal use and for sharing among family and friends (as is evidenced by the large number of amateur music, photo and media sharing web sites). These amateur “content providers” have many of the same concerns as commercial content providers (management of content, re-purposing of content based on consumer/device capabilities, protection of rights, protection from unauthorised access/modification, protection of privacy of providers and consumers, etc.).

Such developments provide new models for distributing and trading digital content electronically in addition to existing business models for trading physical goods. Such new business models mean that the boundaries between the delivery of audio sound (music and spoken word), accompanying artwork (graphics), text (lyrics), video (visual) and synthetic spaces will become increasingly blurred. Indeed, it is becoming increasingly difficult to separate the different intellectual property rights that are associated with multimedia content from the content itself. New solutions are required to manage the access and delivery process of these different content types in an integrated and harmonized way, entirely transparent to the user of multimedia services.

This motivates the MPEG-21 Multimedia Framework initiative that aims to enable transparent and augmented use of multimedia resources across a wide range of networks and devices, specifically taking into account Intellectual Property Management and Protection and the heterogeneity of the access and delivery infrastructure.

VIII © ISO/IEC 2003 — All rights reserved

WORKING DRAFT ISO/IEC PDTR 21000-1

Information technology — Multimedia framework (MPEG-21) — Part 1: Vision, Technology and Strategy

1 Scope

This Technical Report has been prepared within ISO/IEC JTC 1/SC 29/WG 11 to reflect the progress made on the definition of the MPEG-21 Multimedia Framework. This progress is a result of the combination of WG 11’s efforts to standardise the parts of the multimedia framework where it has the appropriate expertise, and the integration with standards initiatives which are being developed by other bodies. The intention of collaborative approach is to maximise harmonisation of efforts and enable effective standards solutions to be implemented in the shortest possible time.

The Technical Report is introduced by a problem statement and a solution statement. The problem statement describes a multimedia usage environment founded upon ubiquitous networks that is encouraging new business models for trading digital content. In this environment, the distinction between content types is less clear as their integration as multimedia resources in new products and services makes the traditional boundaries less distinct. In addition, individuals are becoming increasingly aware of the value, both commercial and intrinsic, of their own digital asset resources and new possibilities presented by the tools which enable them to create and collect, package and distribute content. The solution statement introduces the vision of the Multimedia Framework to support transactions that are interoperable and highly automated, which is required to support these new types of commerce.

This MPEG-21 Multimedia Framework is based on two essential concepts: the definition of a fundamental unit of distribution and transaction (the Digital Item) and the concept of Users interacting with Digital Items. The Digital Items can be considered the “what” of the Multimedia Framework (e.g., a video collection, a music album) and the Users can be considered the “who” of the Multimedia Framework.

The goal of MPEG-21 can be phrased as: defining the technology needed to support Users to exchange, access, consume, trade and otherwise manipulate Digital Items in an efficient, transparent and interoperable way. This Technical Report gives an overview of the technologies that have been identified to enable this goal (and that are consequently being reflected into the different parts of the MPEG-21 standard).

In creating its definition of a multimedia framework and in making its proposals and recommendations for further standardisation, MPEG-21 is taking into account other related multimedia activities. The Technical Report identifies other multimedia initiatives that are currently in progress that are considered as candidates for future interaction and collaboration with the standards work plan agreed by MPEG-21 (see also Annex A).

2 Terms and Definitions

For the purposes of this Technical Report, the following key terms and definitions apply across all parts of the standard:

2.1Digital ItemA Digital Item is a structured digital object with a standard representation, identification and metadata within the MPEG-21 framework. This entity is also the fundamental unit of distribution and transaction within this framework.

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WORKING DRAFT ISO/IEC PDTR 21000-1

2.2End UserA User taking the role of consumer, i.e. being at the end of a value or delivery chain (a human consumer, an agent operating on behalf of a human consumer, etc.). Note: “User” refers to all participants in the value or delivery chain.

2.3PeerA Peer is a device or application that compliantly processes a Digital Item2) .

2.4ResourceA resource is an individually identifiable asset such as a video or audio clip, an image, or a textual asset. A resource may also potentially be a physical object.

2.5UserUser of a system. This includes all members of the value chain (e.g., creator, rights holders, distributors and consumers of Digital Items).

3 Symbols and Abbreviated terms

3.1APIApplication Program Interface

3.3CATVCommunity Aerial Television

3.4CDCompact Disc

3.8DIDigital Item

3.9DIADigital Item Adaptation

3.10DIBODigital Item Base Operations

3.11DIDDigital Item Declaration

2) The term “Terminal” is usually avoided within the MPEG-21 documents because of its connotation as being the end point in a chain of communication. Besides such applications, the term Peer explicitly also includes devices or applications that create or alter Digital Items, and that handle Digital Items “in transit”. How compliance will be achieved is currently being discussed.


3.12DIIDigital Item Identification

3.13DIPDigital Item Processing

3.14DIMEDigital Item Method Engine

3.15DMIFMultimedia Integration Framework

3.16DVBDigital Video Broadcasting

3.17ECMAEuropean Computer Manufacturer Association

3.18HTMLHypertext Mark-up Language

3.19IDIDentifier

3.20IEEEInstitute of Electrical and Electronic Engineers

3.21IPMPIntellectual Property Management and Protection

3.22ITUInternational Telecommunication Union

3.23JPEGJoint Photographic Experts Group

3.24MHPMultimedia Home Platform

3.25LANLocal Area Network

3.26MIDIMusical Industry Digital Interface


3.27MPEGMotion Picture Expert Group

3.28MSFMultiservice Switching Forum

3.29QoSQuality of Service

3.30SGMLStandard Generalised Mark-up Language

3.31SNRSignal to Noise ratio

3.32TRTechnical Report

3.33TVTeleVision

3.34VRMLVirtual Reality Modelling Language

3.35VODVideo Object Decoder

3.36XMLeXtensible Mark-up Language

Structure of the Technical Report

The Technical Report is introduced by a problem statement and a solution statement. The problem statement describes a multimedia usage environment founded upon ubiquitous networks that is encouraging new business models for trading digital content. The solution statement introduces the vision of the Multimedia Framework to support transactions that are interoperable and highly automated, which is required to support these new types of commerce.

Then, the two essential concepts of the Multimedia Framework are introduced: the definition of a fundamental unit of distribution and transaction (the Digital Item) and the concept of Users interacting with Digital Items.

Clause 4 provides some brief background on the first edition of this document (ISO/IEC 21000-1:2001). In that document, seven architectural key elements needed to support MPEG-21’s goals have been identified. These architectural key elements eventually lead to the formulation of requirements for the different MPEG-21 parts.

Following the publication of first edition of this Technical Report in 2001 (ISO/IEC 21000-1:2001), MPEG issued various Calls for Proposals based upon requirements have been and are being issued by MPEG. Eventually the responses to the calls result in different parts of the MPEG-21 standard (i.e. ISO/IEC 21000-N)

4 © ISO/IEC 2003 — All rights reserved

after intensive discussion and harmonization efforts. Clause 5 provides a high-level overview of all MPEG-21 parts defined so far.

Clause 6, “MPEG-21 Achievements” lists those MPEG-21 parts that have already reached Final Draft International Standard (FDIS) or Technical Report (TR) status, obviously excluding this document. For each part, the goal and the rationale are listed. Consequently, the resulting key concepts and basic approach are presented. Finally, Clause 7 highlights those MPEG-21 parts that are currently well advanced in MPEG-21.

3.1 Problem Statement

End users’ appetite for content and the accessibility of information is increasing at an incredible pace. Access devices, with a myriad set of differing terminal and network capabilities, are making their way into end users’ lives. Additionally, these access devices are used in different locations and environments. Their users, however, are currently not given tools to deal efficiently with all the intricacies of this new multimedia usage environment.

Enabling “ease of use” is becoming increasingly important as individuals are producing more and more digital media for their personal use and for sharing among family and friends (as is evidenced by the large number of amateur music, photo and media sharing web sites). These “content providers” have many of the same concerns as commercial content providers (management of content, re-purposing content based on consumer/device capabilities, protection of rights, protection from unauthorised access/modification, protection of privacy of providers and consumers, etc.).

Such developments rewrite existing business models for trading physical goods with new models for distributing and trading digital content electronically. Indeed, it is becoming increasingly difficult to separate the different intellectual property rights that are associated with multimedia content from the content itself. The boundaries between the delivery of audio sound (music and spoken word), accompanying artwork (graphics), text (lyrics), video (visual) and synthetic spaces will become increasingly blurred. New solutions are consequently required to manage the access and delivery process of these different content types in an integrated and harmonized way, entirely transparent to the user of multimedia services.

3.2 Solution Statement

Normative technology is required to enable interoperable new multimedia usage cases. MPEG’s approach is to define a Multimedia Framework to ensure that the systems that deliver multimedia content are interoperable and that transactions are simplified and, if possible, automated. This should apply to the infrastructure requirements for content delivery, content security, rights management, secure payment, and the technologies enabling them – and this list is not exhaustive.

The scope of MPEG-21 could therefore be described as the integration of the critical technologies enabling transparent and augmented use of multimedia resources across a wide range of networks and devices to support functions such as: content creation, content production, content distribution, content consumption and usage, content packaging, intellectual property management and protection, content identification and description, financial management, user privacy, terminals and network resource abstraction, content representation and event reporting.

From its background in key technology and information management standards related to the management, delivery and representation of multimedia content, MPEG was well positioned to initiate such an activity. However, MPEG has recognised from the very start of MPEG-21 that the integration of disparate multimedia technologies can only be achieved by working in collaboration with other bodies.

3.3 Normative Implications

The Multimedia Framework is being developed through a combination of MPEG’s efforts to standardise the parts of the Multimedia Framework where it has the appropriate expertise, and the integration with other multimedia initiatives which have been or are being developed by other bodies. MPEG hence contributes to the definition of the Multimedia Framework by developing new standards or by developing interfaces for other existing or future standards and services to provide the required interoperability or architectural elements.


MPEG-21’s normative recommendations will be determined by interoperability requirements, and their level of detail may vary for each framework element. The actual instantiation and implementation of the framework elements below the abstraction level required to achieve interoperability, will not be specified.

MPEG-21 also provides several non-normative Technical Reports providing information on how to best use MPEG-21 technology.

3.4 Conformance and Reference Software

Conformance is an essential element of each MPEG standard. However, within the scope of this Technical Report, no conformance criteria are given. Instead, Part 14 of MPEG-21 (ISO/IEC 21000-14) will contain such criteria; they are currently under development.

A similarly important issue, reference software, is also not addressed in this Technical Report. It will be covered in ISO/IEC 21000-8, though.

3.5 Description of a Multimedia Framework Architecture

To define where standards are required in a Multimedia Framework which is capable of supporting the delivery of digital content, it is necessary first to reach a shared understanding about common concepts. This presents a difficulty, as there are many examples of different architectures that evolve in response to a variety of models for the use of content. In order to avoid giving undue preference to one model above another, it is proposed to describe the multimedia framework as a generic architecture of conceptual design. Such a broad and high-level approach will allow for more specific use cases to be elaborated, which can be mapped back against the generic architecture as the work continues.

The intent is to maintain an MPEG-21 Use Case Scenario document in conjunction with the Technical Report to provide examples of potential MPEG-21 applications.

MPEG-21 is based on two essential concepts: the definition of a fundamental unit of distribution and transaction (the Digital Item) and the concept of Users interacting with Digital Items. The Digital Items can be considered the “what” of the Multimedia Framework (e.g., a video collection, a music album) and the Users can be considered the “who” of the Multimedia Framework.

The goal of MPEG-21 can thus be rephrased to: defining the technology needed to support Users to exchange, access, consume, trade and otherwise manipulate Digital Items in an efficient, transparent and interoperable way.

During the MPEG-21 standardization process, Calls for Proposals based upon requirements have been and are being issued by MPEG. The responses to the calls lead to the development of different parts of the MPEG-21 standard (i.e. ISO/IEC 21000-N).

3.5.1 Digital Items

A Digital Item is a structured digital object with a standard representation, identification and metadata within the MPEG-21 framework. This entity is the fundamental unit of distribution and transaction within this framework.

MPEG-21 describes a set of abstract terms and concepts to form a useful model for defining Digital Items (Digital Item Declaration). Within this model, a Digital Item is the digital representation of “a work”, and as such, it is the unit that is acted upon (managed, described, exchanged, collected, etc.) within the model. The goal of this model is to be as flexible and general as possible, while providing for the “hooks” that enable higher-level functionality. This, in turn, allows the model to serve as a key foundation in the building of higher-level models in other MPEG-21 elements.

In practice, a Digital Item is a combination of resources, metadata, and structure. The resources are the individual assets or (distributed) content. The metadata de-scribes (distributed) data about or pertaining to the


Digital Item as a whole or also to the individual resources in the Digital Item. Finally, the structure relates to the relationships among the parts of the Digital Item, both resources and metadata.

An example of a Digital Item may be a music compilation including the music but also photos, videos, animation graphics, lyrics, scores, MIDI files, interviews with the singers, news related to the songs, statements by an opinion maker, ratings of an agency, position in the hit list, navigational information driven by user preferences, bargains, etc.

3.5.2 Users

In MPEG-21 a User (with capitalized “U”) is any entity that interacts in the MPEG-21 environment or makes use of Digital Items. Such Users e.g., include individuals, consumers, communities, organizations, corporations, consortia, and governments. Users are identified specifically by their relationship to another User for a certain interaction. From a purely technical perspective, MPEG-21 makes no distinction between a “content provider” and a “consumer”—both are Users. A single entity may use content in many ways (publish, deliver, consume, etc.), and so all parties interacting within MPEG-21 are categorized as Users equally. However, a User may assume specific or even unique rights and responsibilities according to their interaction with other Users within MPEG-21.

At its most basic level, MPEG-21 can be seen as providing a framework in which one User interacts with another User and the object of that interaction is a Digital Item. Some such interactions are creating content, providing content, archiving content, rating content, enhancing and delivering content, aggregating content, delivering content, syndicating content, retail selling of content, consuming content, subscribing to content, regulating content, facilitating transactions that occur from any of the above, and regulating transactions that occur from any of the above. Any of these are “uses” of MPEG-21, and the parties involved are Users.

3.6 Example MPEG-21 Use Case

3.6.1 Introduction

To illustrate the innovative uses MPEG-21 enables, an example use case is described here. For the sake of clarity, it is not intended to cover all MPEG-21 parts and concepts.

Figure 1 — Example Distributed Multimedia System

Consider a distributed multimedia system comprising a certain number of Users exchanging Digital Items across a wide range of networks such as the Internet, mobile phone connections, etc. to a variety of terminals (Figure 1 — Example Distributed Multimedia System).

Rights holders and their authorised representatives will want to set the usage conditions for the different DIs. These can be simple – the Resources of this DI can be used – or it may contain complex conditions – the resources of this DI can be used provided that certain conditions are met, which may, for instance, include


temporal, spatial or group membership provisions. Complex rights expressions of this nature will enable rights holders to develop a multiplicity of business models.

Additionally, in order to guarantee a smooth delivery of such Digital Items over heterogeneous networks “adaptations” of Resources may be required, for example to overcome network congestion or to allow DIs to be routed at the same time to Users connected via mobile devices and to Users on fixed lines. A large number of adaptation possibilities exist, e.g., videos can be adapted by simple frame dropping or by modifying the quantization coefficients. Such adaptations can happen anywhere in the delivery chain from the DI provider to the DI consumer and can be governed by rights expressions.

Assume that a mobile User requests a Digital Item containing the newest movie trailers that are available without payment from another User providing a repository of Digital Items. In addition, the mobile User only accepts videos with a bitrate lower than 500 kbps. On its way to the Digital Item repository, the request for the trailer passes another User that has the functionality of a proxy cache and, fortunately, the requested resource is cached there. Assume, however, that the bandwidth requirement of the cached version exceeds the resource constraints.

Based on watching the movie trailers, the User decides to watch a movie at high resolution in a stationary environment. This high-resolution version is not free and cannot be redistributed to other Users.

3.7 Enabling MPEG-21 Technologies

This subclause highlights MPEG-21 technologies that enable the above use case. For the sake of clarity, only a subset of these technologies are listed.

3.7.1.1 Digital Item Declaration

Part 2 of MPEG-21 (ISO/IEC 21000-2) defines the structure of the Digital Item. These Digital Items comprise:

The Digital Item Declaration (DID); and

The Resources.

The DID is an XML file describing the Digital Item whereas the Resources are the individually identifiable multimedia assets of the Digital Item (DI). The DID file may include information such as unique identifiers for the complete DI as well as for Resources, expressions on rights and permissions pertaining to the DI (or parts thereof) and generic metadata describing the Digital Item and its Resources. Finally, the DID contains references to the Resources3) . Typical examples of Resources include AAC audio files, MPEG-2 video clips, JPEG images, MPEG-4 presentations, HTML pages – but also e.g., video clips or text in proprietary formats.

3.7.1.2 Rights Expression Language/Rights Data Dictionary

MPEG-21 Part 5 provides a machine-readable Rights Expression Language (REL) that can declare rights and permissions using the terms as defined in the Rights Data Dictionary (RDD, MPEG-21 Part 6). The provider of the movie will use the REL to express under what conditions which User shall be able to access the item.

After paying for the high-resolution movie, the User will obtain an MPEG-21 REL Grant (e.g., in a second DI) containing the conditions under which the User can view the movie4) . This grant contains four parts:

keyHolder: identifies that the User is being granted the rights;

Play: identifies the permission that the User is being granted; The RDD provides the semantic definition of what this permission includes (in the example, the User is only allowed to render the video);

3) It is however also possible to have Resources contained in the DI itself.

4) It is assumed for the purposes of this license that the authenticity and integrity of the license are determined by other means.


diReference: identifies the Digital Item, e.g., urn:grid:a1-abcde-1234567890-f, that the User is being granted rights to (in accordance with MPEG-21 Part 3, Digital Item Identification5) ); and

validityInterval: identifies the time interval during which the User is allowed to play the Digital Item.

The task of enforcing these rights is the job of the IPMP system (MPEG-21 Part 4).

3.7.1.3 Resource Adaptation

MPEG-21 Part 7 provides the means to steer Resource adaptation, e.g., in the proxy cache, and to carry it out in a more efficient way. The first tool to this end is the DIA AdaptationQoS Descriptor, which specifies the relationship between resource constraints, feasible operations on the resource and associated resulting qualities. The second descriptor is the DIA Bitstream Syntax Description (BSD) which describes the high-level structure of the media bit stream and which is appropriate for the adaptation of media resources on devices with constrained computational or memory resources. The advantage of using a BSD for adaptation is that it has a considerably smaller size than the media described and that adaptation engines need not be aware of the specific coding format of the movie. Rather, an adaptation module may rely on the BSD to modify the description/structure of the bit stream (by “editing” the BSD) and to further generate the adapted media data from the adapted BSD. This results in a more lightweight, coding format-independent way of adapting media streams, as compared e.g., to a sophisticated transcoding technique. Additional MPEG-21 tools provide so-called Usage Environment Descriptors which specify terminal and network characteristics and User preferences, among others.

Let us assume that the Digital Item cached in the proxy cache has, beside the resource, MPEG-7 descriptors available on the media format and media profile, also the AdaptationQoS and a BSD available. The proxy cache has to determine the bandwidth requirements of the version cached. This may be obtained from MPEG-7 descriptors in the Digital Item. The User constraint is then matched against the bandwidth requirement. If an adaptation is required, the AdaptationQoS associated to this video is consulted and the appropriate adaptation operation is extracted, together with a link to the adaptation process, which acts on the BSD description available for the video.

3.8 Activities Related to the Multimedia Framework

In creating its definition of a multimedia framework and making its proposals and recommendations for further standardisation, it is necessary for MPEG to take other related multimedia activities into account. MPEG has hence sought collaboration (e.g., through liaisons) with relevant initiatives to expedite the work.

This Technical Report identifies some other multimedia initiatives that could be considered as potential building blocks or candidates for current and future interaction and collaboration with the standards work plan agreed by MPEG. A non-exhaustive list of these is given in Annex A. The monitoring and updating of these activities is intended to be a continuous MPEG activity. During its previous standards developments, MPEG has always recognised the importance of establishing liaisons with other bodies and organisations with which it shares complementary or common objectives. These liaisons have provided a useful channel for communicating between the parties to ensure that any overlap between concurrent standards activities is minimised and that, where necessary, common technology can be shared.

The broad scope of the task of defining a multimedia framework presents new challenges and opportunities for collaboration between those initiating standards activities in this area. The value of an integrated framework for the management and delivery of multimedia content is considerable and is attracting the interest and enthusiasm of major standards bodies. Overlap between standardisation activities is almost inevitable and demands a consultative approach between those standards bodies which are prepared to meet the challenge to avoid duplication of effort and to maximise interoperability.

Within this Technical Report MPEG is describing a vision of a multimedia framework in order to pinpoint the components of the framework which require further standardisation. However, it makes no assumption that MPEG will undertake the task of actually standardising all of the identified components. Rather, MPEG would like to co-ordinate its work with other standards bodies to ensure that it can concentrate on those areas which

5) The Digital Item Identification specification allows established industry identifiers (e.g. International Standard Book Numbers (ISBN), International Standard Recording Codes (ISRC), etc) to be used in the context of MPEG-21.


are best suited to and compatible with the mandate of MPEG. It is expected that a high level of practical integration with other standards bodies will be necessary in order to complete some standardisation tasks successfully.

4 About ISO/IEC 21000-1:2001

From the very start, MPEG-21 has opted for a User centric approach. The first edition of this document (ISO/IEC 21000-1:2001) identifies and defines the seven architectural key elements needed to support MPEG-21’s goals. Although it was already foreseen that eventually these elements would be elaborated into one or more MPEG-21 parts, this partitioning into seven architectural key elements proved to be an efficient working method to focus efforts when defining and refining the MPEG-21 requirements.

The seven key elements that have been defined in ISO/IEC 21000-1:2001 are:

a) Digital Item Declaration (a uniform and flexible abstraction and interoperable schema for declaring Digital Items);

b) Digital Item Identification and Description (a framework for identification and description of any entity regardless of its nature, type or granularity);

c) Content Handling and Usage (provide interfaces and protocols that enable creation, manipulation, search, access, storage, delivery, and (re)use of content across the content distribution and consumption value chain);

d) Intellectual Property Management and Protection (the means to enable Digital Items and their rights to be persistently and reliably managed and protected across a wide range of networks and devices);

e) Terminals and Networks (the ability to provide interoperable and transparent access to content across networks and terminals);

f) Content Representation (how the media resources are represented);

g) Event Reporting (the metrics and interfaces that enable Users to understand precisely the performance of all reportable events within the framework).

As an example, Digital Item Adaptation (MPEG-21 part 7) addresses requirements initially formulated in the Terminals and Networks architectural key element.

5 Overview of the MPEG-21 Parts

Following the publication of first edition of this Technical Report in 2001 (ISO/IEC 21000-1:2001), MPEG issued various Calls for Proposals based upon requirements have been and are being issued by MPEG. Eventually the responses to the calls result in different parts of the MPEG-21 standard (i.e. ISO/IEC 21000-N) after intensive discussion and harmonization efforts. This new edition aims to reflect the significant progress that was made in developing MPEG-21 since the publication of first edition of this Technical Report (ISO/IEC 21000-1:2001).

An advantage to develop the MPEG-21 standard in several rather independent parts is to allow the various pieces of technology to be useful as stand-alones and thus used as much as possible, even if in conjunction with proprietary technologies. This has been the case, for example, for MPEG-2 Video, which today is being used together with MPEG-2 Systems but not with MPEG-2 Audio in the context of the U.S. digital TV system. However, although the various parts may be used independently, they were developed to give optimal results when they are used together; this principle is particularly important for MPEG-21 since an integrated multimedia framework is the purpose of this standard.


This clause gives a high-level overview of the different MPEG-21 parts that have already been developed or are currently under development. Those most advanced in the standardisation process are further elaborated in Clause 6 and 7.

5.1 Part 1 – Vision, Technologies and Strategy

Part 1 is this document. The title “Vision, Technologies and Strategy” has been chosen to reflect the fundamental purpose of the Technical Report. This is to:

Define a 'vision' for a multimedia framework to enable transparent and augmented use of multimedia resources across a wide range of networks and devices to meet the needs of all users

Achieve the integration of components and standards to facilitate harmonisation of 'technologies' for the creation, management, transport, manipulation, distribution, and consumption of Digital Items.

Define a 'strategy' for achieving a multimedia framework by the development of specifications and standards based on well-defined functional requirements through collaboration with other bodies.

The first edition of this TR is ISO/IEC 21000-1:2001. This document is the second edition.

5.2 Part 2 – Digital Item Declaration (DID)

The purpose of the Digital Item Declaration (DID) specification is to describe a set of abstract terms and concepts to form a useful model for defining Digital Items. Within this model, a Digital Item is the digital representation of “a work”, and as such, it is the thing that is acted upon (managed, described, exchanged, collected, etc.) within the model. The goal of this model is to be as flexible and general as possible, while providing for the “hooks” that enable higher level functionality. This, in turn, will allow the model to serve as a key foundation in the building of higher level models in other MPEG-21 elements (such as Identification & Description or IPMP). This model specifically does not define a language in and of itself. Instead, the model helps to provide a common set of abstract concepts and terms that can be used to define such a scheme, or to perform mappings between existing schemes capable of Digital Item Declaration, for comparison purposes.

The DID technology is described in three normative sections:

Model: The Digital Item Declaration Model describes a set of abstract terms and concepts to form a useful model for defining Digital Items. Within this model, a Digital Item is the digital representation of “a work”, and as such, it is the thing that is acted upon (managed, described, exchanged, collected, etc.) within the model.

Representation: Normative description of the syntax and semantics of each of the Digital Item Declaration elements, as represented in XML. This section also contains some non-normative examples for illustrative purposes.

Schema:Normative XML schema comprising the entire grammar of the Digital Item Declaration representation in XML.

5.3 Part 3 – Digital Item Identification (DII)

ISO/IEC 21000-3 comprises three parts:

The possibility to uniquely identify Digital Items and parts thereof (such as resources) as well as IP related to the Digital Items (such as abstractions). DII provides a schema that can be used to include identifiers into a Digital Item Declaration.

A method how to uniquely identify Description Schemes (using XML namespaces). This element enables the association of well-defined descriptions (so-called metadata) with Digital Items and their parts.

A schema to identify different types of Digital Items, a feature needed by, at least, Digital Item Adaptation.


It should be noted, however, that the DII specification does not specify new identification systems itself. For example, ISO/IEC 21000-3 does not attempt to replace the ISRC (as defined in ISO 3901) for sound recordings but allows ISRCs to be used within MPEG-21. In fact, the DII specification allows for existing and new identification systems to be ingenerated into the MPEG-21 domain through the mechanism of a Registration Authority.

5.4 Part 4 – Intellectual Property Management and Protection (IPMP)

This part of MPEG-21 will define an interoperable framework for Intellectual Property Management and Protection (IPMP). Fairly soon after MPEG-4, with its IPMP hooks, became an International Standard, concerns were voiced within MPEG that many similar devices and players might be built by different manufacturers, all MPEG-4, but many of them not interworking. This is why MPEG decided to start a new project on more interoperable IPMP systems and tools. The project includes standardized ways of retrieving IPMP tools from remote locations, exchanging messages between IPMP tools and between these tools and the terminal. It also addresses authentication of IPMP tools, and has provisions for integrating Rights Expressions according to the Rights Data Dictionary and the Rights Expression Language.

Efforts are currently ongoing to define the requirements for the management and protection of intellectual property in the various parts of the MPEG-21 standard currently under development.

5.5 Part 5 – Rights Expression Language (REL)

Following an extensive requirements gathering process, which started in January 2001, MPEG issued a Call for Proposals during its July meeting in Sydney for a Rights Data Dictionary (RDD) and a Rights Expression Language (REL). Responses to this Call were processed during the December 2001 meeting in Pattaya and the evaluation process established an approach for going forward with the development of a specification, expected to be an International Standard in late 2003.

A Rights Expression Language is seen as a machine-readable language that can declare rights and permissions using the terms as defined in the Rights Data Dictionary.

The REL is intended to provide flexible, interoperable mechanisms to support transparent and augmented use of digital resources in publishing, distributing, and consuming of digital movies, digital music, electronic books, broadcasting, interactive games, computer software and other creations in digital form, in a way that protects digital content and honours the rights, conditions, and fees specified for digital contents. It is also intended to support specification of access and use controls for digital content in cases where financial exchange is not part of the terms of use, and to support exchange of sensitive or private digital content.

Each REL Grant contains four elements;

a) Permission - this articulates what usage of the Digital Item one user is providing to another.

b) Condition - this articulate the constraint that the first user places on the second as a result of the use of their Digital Item. Example: you can play my movie, in return for a payment of $1. This statement includes the Permission "You can play my movie" and the condition "in return for $1".

c) Principle - this identifies exactly the User to who the Permission is being granted. i.e. "User XXX (You) can play my movie".

d) Resource - this identifies exactly the Digital Item (or part thereof) for which a Permission is being granted. E.g., "User XXX can play Item YYY (my movie)".

From this simple model of Grant =Permission + Condition + Principle + Resource very flexible rights expression can be generated.

The Rights Expression Language is intended to provide a flexible interoperable mechanism to ensure personal data is processed in accordance with individual rights and to meet the requirement for Users to be able to express their rights and interests in a way that addresses issues of privacy and use of personal data.


The standard Rights Expression Language is able to support guaranteed end-to-end interoperability, consistency and reliability between different systems and services. To do so, it must offer richness and extensibility in declaring rights, conditions and obligations, ease and persistence in identifying and associating these with digital contents, and flexibility in supporting multiple usage/business models.

MPEG has developed its REL to meet the requirements it defined. MPEG recognizes that several industries and User communities will need to modify the language to better meet their specific needs. To facilitate easy mapping of the REL to these industry specific applications MPEG has developed a process of Extension and Profiling of the Language.

The Extension process allows individuals to define elements of the language specific to their needs. This includes development of new verbs and schematic elements to improve efficiency in their specific domain. MPEG has also developed the Rights Data Dictionary to ensure the semantic interpretation of new verbs is unambiguously understood to promote interoperability.

The Profile process allows individuals to select only the parts of the language applicable to their application. This optimizes payload of Digital items and computation requirements of MPEG terminals. MPEG recognizes that different applications require different levels of complexity and flexibility in the REL. The Profiling process allows one community to select only the elements they feel they need to meet a specific application need.

It is important to note that an Extension and Profile can be used concurrently to optimise the applicability of the REL to one specific application.

5.6 Part 6 – Rights Data Dictionary (RDD)

Following the evaluation of submissions in response to a Call for Proposals the specification of a Rights Data Dictionary (RDD) began in December 2001. The working draft was refined at the following three meetings and a Committee Draft published in July 2002. The following points summarise the scope of this specification:

The Rights Data Dictionary (RDD) comprises a set of clear, consistent, structured, integrated and uniquely identified Terms to support the MPEG-21 Rights Expression Language.

The structure of the dictionary is specified, along with a methodology for creating the dictionary. The means by which further Terms may be defined is also explained.

The Dictionary is a prescriptive Dictionary, in the sense that it defines a single meaning for a Term represented by a particular RDD name (or Headword), but it is also inclusive in that it recognizes the prescription of other Headwords and definitions by other Authorities and incorporates them through mappings. The RDD also supports the circumstance that the same name may have different meanings under different Authorities. The RDD specification has audit provisions so that additions, amendments and deletions to Terms and their attributes can be tracked.

RDD recognises legal definitions as and only as Terms from other Authorities that can be mapped into the RDD. Therefore Terms that are directly authorized by RDD neither define nor prescribe intellectual property rights or other legal entities.

As well as providing definitions of Terms for use in the REL, the RDD specification is designed to support the mapping and transformation of metadata from the terminology of one namespace (or Authority) into that of another namespace (or Authority) in an automated or partially-automated way, with the minimum ambiguity or loss of semantic integrity.

The dictionary is based on a logical model (the Context Model) which is the basis of the dictionary ontology. The model is described in detail in a normative annex to the specification. It is based on the use of verbs which are contextualised so that a dictionary created using the model with it can be as extensible and granular are required. An annex explaining how the model can be applied to generate new Terms is also provided.


5.7 Part 7 – Digital Item Adaptation (DIA)

One of the goals of MPEG-21 is to achieve interoperable transparent access to (distributed) advanced multimedia content by shielding users from network and terminal installation, management and implementation issues. This will primarily enable the provision of network and terminal resources on demand so that multimedia content can be created and ubiquitously shared, always with the agreed/contracted quality, reliability and flexibility.

Towards this goal, the adaptation of Digital Items is required. As shown in Figure 2, Digital Items are subject to a resource adaptation engine, as well as a descriptor adaptation engine, which together produce the adapted Digital Items. The target for this part of the standard is to specify tools that provide input to the adaptation engine, so that any constraints on the delivery and consumption of resources can be satisfied, and the quality of the user experience can be guaranteed.

It is important to emphasise that the adaptation engines themselves are non-normative tools of Digital Item Adaptation. However, descriptions and format-independent mechanisms that provide support for Digital Item Adaptation in terms of resource adaptation, descriptor adaptation, and/or Quality of Service management are within the scope of this part of the standard.

Digital Item AdaptedDigital Item

DIA Tools

Digital ItemAdaptation Engine

ResourceAdaptation Engine

DescriptionAdaptation Engine

Scope of standardization

Digital Item AdaptedDigital Item

DIA Tools

Digital ItemAdaptation Engine

ResourceAdaptation Engine

DescriptionAdaptation Engine



Figure 2 — Illustration of Digital Item Adaptation

5.8 Part 8 – Reference Software

The part of MPEG-21 that has most recently been identified as a candidate for specification is Reference Software. Reference software will form the first of what is envisaged to be a number of systems-related specifications in MPEG-21. Other candidates for specification are likely to include a binary representation of the Digital Item Declaration and an MPEG-21 file format.

The development of the Reference Software will be based on the requirements that have been defined for an architecture for processing Digital Items.

5.9 Part 9 – File Format

An MPEG-21 Digital Item can be a complex collection of information. Both still and dynamic media (e.g., images and movies) can be included, as well as Digital Item information, metadata, layout information, and so on. It can include both textual data (e.g., XML) and binary data (e.g., an MPEG-4 presentation or a still picture). For this reason, the MPEG-21 file format inherits several concepts from MP4, in order to make 'multi-purpose' files possible. A dual-purpose MP4 and MP21 file, for example, would play just the MPEG-4 data on an MP4 player, and would play the MPEG-21 data on an MP21 player. A 'resource map' allows the inclusion of multiple referenced resources in the same or other files, and for systems-level management of those resources (e.g., consolidating them into one file, or compacting a file). The DID and resources can also be protected.


5.10 Part 10 – Digital Item Processing (DIP)

The Digital Item Declaration Language, as it is currently standardized, is an XML language for defining a Digital Item. This implies that a Digital Item Declaration is, as it should be, a static declaration. Digital Item Methods allow the User to add functionality to a Digital Item Declaration.

The standardization of Digital Item Processing allows interoperability at the processing level. The main idea behind the Digital Item Processing Architecture is that, on receipt of a DID, a list of DI Methods that can be applied to the Digital Item is presented to the User. The User chooses one Method that is then executed by the DIP Engine.

5.11 Part 11 – Evaluation Methods for Persistent Association Technologies

This Technical Report documents best practice in the evaluation of persistent association technologies, i.e., technologies that link information to identify and describe content using the content itself. This part does not contain any normative behaviour.

The purpose of this part is to allow evaluations of such technologies to be conducted using a common methodology rather than to standardise the technologies themselves. This is intended to give confidence to those relying on the technologies that the results are:

Appropriate tests of the technology that will predict performance under real-world conditions

Comparable with results obtained from other tests conducted using the same methodology.

This Technical Report focuses on the evaluation of two classes of technology: watermarks and fingerprints when applied to audio. It is expected that the scope of this Technical Report may be enhanced in future to cover other media types including still pictures.

5.12 Part 12 – Test Bed for MPEG-21 Resource Delivery

This part provides a (software-based) test bed for (i) the delivery of scalable media delivery, and (ii) testing/evaluating this scalable media delivery in streaming environments (e.g., by taking into account varying network environments).

5.13 Part 13 – Scalable Video Coding

One important application requirement in the MPEG-21 multimedia framework is efficient and seamless scalable coding. This means that compression efficiency should not be inferior when compared to non-scalable coders. Further, scalability should include different dimensions: spatial, temporal, SNR and complexity. Even though this had been a goal in the development of previous MPEG standards, it has not been achieved in a generic sense, because of sacrifice in performance. Hence, technologies such as wavelet coding which inherently possess scalability features can be potential candidates to achieve this objective, if their performance matches the state of the art.

A video coding technology providing flexible scalability of a single bitstream allows seamless integration of servers, heterogeneous networks, terminals, acquisition and storage devices with different characteristics in the MPEG-21 multimedia framework. Examples of potential applications that can benefit from such improved scalable coding technologies are: Internet video, wireless LAN video, mobile wireless video for conversational, VOD, and live broadcasting purposes, multi-channel content production and distribution, surveillance-and-storage applications, and layered protection of contents.

Moreover, efficient scalable coding can be useful for error resilience, if the common practice of unequal error protection is applied. In particular, a non-recursive coder, which is necessary for a high freedom to scalability, also prevents effects of error propagation as a by-product.

Other requirements which may be interesting are :


A unique scalable solution serving broad range of rates, qualities and formats, potentially extending the definition of conformance points

Support for complexity scalability by limiting the impact of incomplete decoding, allow to break decoding at any point to achieve a high degree of freedom in the design of complexity-scalable decoders.

Temporal random access in both streaming and storage related applications. For storage, as further requirements, reverse play, fast forward/reverse, efficient editing and coding of manipulated frames.

As the first important application requirement, scalability with high flexibility, arbitrary combination of spatial, temporal and SNR is identified. In particular, transmission over variable-bandwidth networks, storage and different-capability display devices would benefit from such functionality. Multicast/broadcast over variable-bandwidth networks might be seen as potential major application, also in combination with storage on servers or in home networks or for surveillance applications. Environments with "encoding once, decoding multiple times at various rates and resolutions" paradigm would have high advantage in costs. However, an important constraint is that scalable coding should cost nothing noticeable in terms of rate-distortion performance and complexity compared to state-of-the art single-layer coders. Efficient scalable representations can easily provide QoS capabilities, regardless of the provisions offered by the network. This will establish a perfect complement with other MPEG-21 technology such as DIA.

6 MPEG-21 Achievements

6.1 Introduction

This clause lists those MPEG-21 parts, introduced in Clause 5, that have already reached Final Draft International Standard (FDIS) or Technical Report (TR) status, obviously excluding this document (ISO/IEC 21000-1). For each part, the goal and the rationale are listed. Consequently, the resulting key concepts and basic approach are presented.

6.2 ISO/IEC 21000-2: Digital Item Declaration (DID)

6.2.1 Goal

To establish a uniform and flexible model and interoperable representation schema for defining Digital Items.

6.2.2 Rationale

Within any system (such as MPEG-21) that proposes to facilitate a wide range of actions involving Digital Items, there is a strong need for a concrete representation of any individual Digital Item. Clearly there are many kinds of content, and probably just as many possible ways of representing it. This presents a strong challenge to design a powerful and flexible model for Digital Items that accommodates the many types of content, as well as any and all new forms it may assume in the future. Such a model is only truly useful if it yields a schema that can be used to unambiguously represent and interoperably communicate about any Digital Items defined within the model.

6.2.3 Key concepts and basic approach

The purpose of the Digital Item Declaration (DID) specification is to describe a set of abstract terms and concepts to form a useful model for defining Digital Items. Within this model, a Digital Item is the digital representation of “a work”, and as such, it is the thing that is acted upon (managed, described, exchanged, collected, etc.) within the model. The goal of this model is to be as flexible and general as possible, while providing for the “hooks” that enable higher-level functionality. This, in turn, will allow the model to serve as a key foundation in the building of higher-level models in other MPEG-21 elements (such as Identification & Description or IPMP). This model specifically does not define a language in and of itself. Instead, the model helps to provide a common set of abstract concepts and terms that can be used to define such a scheme, or to perform mappings between existing schemes capable of Digital Item Declaration, for comparison purposes.


The DID technology is described in three normative sections:

Model: The Digital Item Declaration Model describes a set of abstract terms and concepts to form a useful model for defining Digital Items. Within this model, a Digital Item is the digital representation of “a work”, and as such, it is the thing that is acted upon (managed, described, exchanged, collected, etc.) within the model.

Representation: Normative description of the syntax and semantics of each of the Digital Item Declaration elements, as represented in XML. This section also contains some non-normative examples for illustrative purposes.

Schema:Normative XML schema comprising the entire grammar of the Digital Item Declaration representation in XML.

The following subclauses describe the semantic “meaning” of the principle elements of the Digital Item Declaration Model. Please note that in the descriptions below, the defined elements in italics are intended to be unambiguous terms within this model.

6.2.3.1 Container

A container is a structure that allows items and/or containers to be grouped. These groupings of items and/or containers can be used to form logical packages (for transport or exchange) or logical shelves (for organization). Descriptors allow for the “labelling” of containers with information that is appropriate for the purpose of the grouping (e.g. delivery instructions for a package, or category information for a shelf).

It should be noted that a container itself is not an item; containers are groupings of items and/or containers.

6.2.3.2 Item

An item is a grouping of sub-items and/or components that are bound to relevant descriptors. Descriptors contain information about the item, as a representation of a work. Items may contain choices, which allow them to be customized or configured. Items may be conditional (on predicates asserted by selections defined in the choices). An item that contains no sub-items can be considered an entity -- a logically indivisible work. An item that does contain sub-items can be considered a compilation -- a work composed of potentially independent sub-parts. Items may also contain annotations to their sub-parts.

The relationship between items and Digital Items (as defined in ISO/IEC 21000-1:2001, MPEG-21 Vision, Technologies and Strategy) could be stated as follows: items are declarative representations of Digital Items.

6.2.3.3 Component

A component is the binding of a resource to all of its relevant descriptors. These descriptors are information related to all or part of the specific resource instance. Such descriptors will typically contain control or structural information about the resource (such as bit rate, character set, start points or encryption information) but not information describing the “content” within.

It should be noted that a component itself is not an item; components are building blocks of items.

6.2.3.4 Anchor

An anchor binds descriptors to a fragment, which corresponds to a specific location or range within a resource.

6.2.3.5 Descriptor

A descriptor associates information with the enclosing element. This information may be a component (such as a thumbnail of an image, or a text component), or a textual statement.


6.2.3.6 Condition

A condition describes the enclosing element as being optional, and links it to the selection(s) that affect its inclusion. Multiple predicates within a condition are combined as a conjunction (an AND relationship). Any predicate can be negated within a condition. Multiple conditions associated with a given element are combined as a disjunction (an OR relationship) when determining whether to include the element.

6.2.3.7 Choice

A choice describes a set of related selections that can affect the configuration of an item. The selections within a choice are either exclusive (choose exactly one) or inclusive (choose any number, including all or none).

6.2.3.8 Selection

A selection describes a specific decision that will affect one or more conditions somewhere within an item. If the selection is chosen, its predicate becomes true; if it is not chosen, its predicate becomes false; if it is left unresolved, its predicate is undecided.

6.2.3.9 Annotation

An annotation describes a set of information about another identified element of the model without altering or adding to that element. The information can take the form of assertions, descriptors, and anchors.

6.2.3.10 Assertion

An assertion defines a full or partially configured state of a choice by asserting true, false or undecided values for some number of predicates associated with the selections for that choice.

Figure 3 — Relationship of the principle elements within the Digital Identification Declaration Model


6.2.3.11 Resource

A resource is an individually identifiable asset such as a video or audio clip, an image, or a textual asset. A resource may also potentially be a physical object. All resources must be locatable via an unambiguous address.

6.2.3.12 Fragment

A fragment unambiguously designates a specific point or range within a resource. Fragment may be resource type specific.

6.2.3.13 Statement

A statement is a literal textual value that contains information, but not an asset. Examples of likely statements include descriptive, control, revision tracking or identifying information.

6.2.3.14 Predicate

A predicate is an unambiguously identifiable Declaration that can be true, false or undecided.

The above figure (Figure 3 — Relationship of the principle elements within the Digital Identification DeclarationModel) is an example showing the most important elements within this model, how they are related, and as such, the hierarchical structure of the Digital Item Declaration Model.

6.3 ISO/IEC 21000-3: Digital Item Identification (DII)

6.3.1 Goal

To enable the unique identification of Digital Items, different Digital Item Types (which is needed for subsequent Parts of MPEG-21) and metadata schemes for describing Digital Items.

6.3.2 Rationale

The unique identification of Digital Items and the ascription of metadata to Digital Items, are crucial elements in many applications within MPEG-21’s domain and have been successfully used in many areas. For example, ISBNs6) are used in the book industry in conjunction with a set of metadata to uniquely identify and describe books. This has enabled publishers and booksellers to manage their stock as well as customers to easily search and purchase books, especially in eCommerce transactions. Similar applications in the digital world are similarly dependent on unique and persistent (see Subclause 5.11) identification of Digital Items and their parts and the ability to associate well-formed metadata with such items.

Furthermore, to allow the identification of Digital Items themselves, DII needs to enable the association of a “related identifier” with a Digital Item (or part thereof). This latter concept is necessary to, for example, associate identifiers to intellectual property rights related to Digital Items (e.g. an ISWC7) )

As Digital Items come in two different “types” (Content Digital Item and Context Digital Item, see subclauses on Digital Item Adaptation), DII needs to provide means to distinguishing such types.


DII works in close conjunction with the Digital Item Declaration Language as provided in Part 2 and provides a set of XML elements that allow the inclusion of content identifiers and DI type identifiers into Digital Item Declarations.

6) International Standard Book Number

7) International Standard Work Code


In addition, DII uses the XML namespace mechanism to allow the identification of metadata schemes that can be used to describe Digital Items.

6.4 ISO/IEC 21000-5: Rights Expression Language (REL)

6.4.1 Goal

To promote an interoperable multimedia framework where the creators of Digital Item can express flexibly and unambiguously, the permission they wish to provide to Users regarding the usage of their Digital Items.

6.4.2 Rationale

By developing a well structured, flexibly and unambiguous machine-readable language, the objectives of an interoperable multimedia framework respecting the creators’ permissions can be realized.


MPEG REL adopts a simple and extensible data model for many of its key concepts and elements.

The MPEG REL data model for a rights expression consists of four basic entities and the relationship among those entities. This basic relationship is defined by the MPEG REL assertion “grant”. Structurally, an MPEG REL grant consists of the following (Figure 4 — The REL Data Model):

The principal to whom the grant is issued;

The right that the grant specifies;

The resource to which the right in the grant applies; and

The condition that must be met before the right can be exercised.

Right

Resource ConditionPrincipal

Associated with

Subject toIssued to Right

Resource ConditionPrincipal

Associated with

Subject toIssued to

Figure 4 — The REL Data Model

6.4.3.1 Principal

A principal encapsulates the identification of principals to whom rights are granted. Each principal identifies exactly one party. In contrast, a set of principals, such as the universe of everyone, is not a principal.

A principal denotes the party that it identifies by information unique to that individual. Usefully, this is information that has some associated authentication mechanism by which the principal can prove its identity. The Principal type supports the following identification technologies:

A principal that must present multiple credentials, all of which must be simultaneously valid, to be authenticated;


A keyHolder, meaning someone identified as possessing a secret key such as the private key of a public / private key pair; and

Other identification technologies that may be invented by others.

6.4.3.2 Right

A right is the "verb" that a principal can be granted to exercise against some resource under some condition. Typically, a right specifies an action (or activity) or a class of actions that a principal may perform on or using the associated resource.

MPEG REL provides a right element to encapsulate information about rights and provides a set of commonly used, specific rights, notably rights relating to other rights, such as issue, revoke and obtain. Extensions to MPEG REL could define rights appropriate to using specific types of resource. For instance, the MPEG REL content extension defines rights appropriate to using digital works (e.g., play and print).

6.4.3.3 Resource

A resource is the "object" to which a principal can be granted a right. A resource can be a digital work (such as an e-book, an audio or video file, or an image), a service (such as an email service, or B2B transaction service), or even a piece of information that can be owned by a principal (such as a name or an email address).

MPEG REL provides mechanisms to encapsulate the information necessary to identify and use a particular resource or resources that match a certain pattern. The latter allows identification of a collection of resources with some common characteristics. Extensions to MPEG REL could define resources appropriate to specific business models and technical applications.

6.4.3.4 Condition

A condition specifies the terms, conditions and obligations under which rights can be exercised. A simple condition is a time interval within which a right can be exercised. A slightly complicated condition is to require the existence of a valid, prerequisite right that has been issued to some principal. Using this mechanism, the eligibility to exercise one right can become dependent on the eligibility to exercise other rights.

MPEG REL defines a condition element to encapsulate information about conditions and some very basic conditions. Extensions to MPEG REL could define conditions appropriate to specific distribution and usage models. For instance, the MPEG REL content extension defines conditions appropriate to using digital works (e.g., watermark, destination, and renderer).

6.4.3.5 Relationship with MPEG terminology

The entities in the MPEG REL data model: “principal”, “right”, “resource”, and “condition”, can correspond to (but are not necessarily equivalent to) to “User” including “terminal”, “right”, “Digital Item” and “condition” in the MPEG-21 terminology.

6.4.3.6 Encapsulated in XML Schema

Since MPEG REL is defined using the XML Schema recommendation from W3C, its element model follows the standard one that relates its elements to other classes of elements. For example, the “grant” element is related to its child elements, “principal”, “right”, “resource” and “condition”.


6.5 ISO/IEC 21000-6: Rights Data Dictionary (RDD)

6.5.1 Goal

To provide a set of clear, consistent, structured, integrated and uniquely identified Terms to support the MPEG-21 Rights Expression Language (REL), ISO/IEC 21000-5 and to support the mapping of Terms from different namespaces.

6.5.2 Rationale

It is widely recognised that there is a need for semantic standards in the area of digital rights management. Not only are unambiguous semantics essential for the Rights Expression Language, but their lack has been a basic inhibitor of progress towards interoperability in that there can be no satisfactory way of exchanging data between different proprietary digital rights management applications. With such semantic standards every communication will depend on imprecise and unmaintainable many-to-many semantic mappings. This will be costly and de-incentivising for rights holders, who will have to bear the cost. In turn, this will damage the interests of DRM companies that will depend on a plentiful supply of interoperable content (interoperable because it is identified and described in a consistent manner). In short, for everyone involved, the cost of maintaining communications between proprietary applications without a standard semantic layer will be unsupportable.

6.5.3 Key concepts

6.5.3.1 RDD Database

The tool containing the RDD Dictionary and supporting its maintenance.

6.5.3.2 RDD Dictionary

The Terms and their TermAttributes defined according to this Standard.

6.5.3.3 RDD System

A system comprising the RDD Dictionary, the RDD Database and the specifications contained in Annex A.

6.5.3.4 RDD Registration Authority

The Registration Authority appointed to administer this Standard.

6.5.3.5 Term

Term is defined in the RDD Dictionary as “A semantic element with a defined Meaning and an RddIdentifier”. A Term is the basic unit of the RDD Dictionary structure. Terms have up to twelve standardised attributes.

6.5.3.6 RddIdentifier

RddIdentifier is defined in the RDD Dictionary as “the unique Identifier of a Term in the RDD Dictionary”.

6.5.3.7 Headword

Headword is defined in the RDD Dictionary as “The primary, human-readable Name of a Term according to its Authority”.


6.5.3.8 Term Description

TermDescription is defined in the RDD Dictionary as “A natural language Description of the Meaning of a Term.”

6.5.3.9 The Context Model

The fundamental building block of the RDD Ontology. The ContextModel defines a group of five Terms (the “BasicTermSet”) with associated Classes and RelatingTerms whose application to a specific ActType or ContextType results in the definition of a Family group of new Terms with DerivedMeanings and PartlyDerivedMeanings.

6.5.3.10 Family

Family is defined in the RDD Dictionary as “A group of Relationships that determine attribute inheritance from one Term to others according to the ContextModel”. There are two Types of Families of Terms: ActionFamily and ContextFamily.

7 Highlights of the MPEG-21 Parts under Development

This clause gives a more detailed insight in the MPEG-21 parts that are currently well advanced in MPEG-21. For each part, the goal and the rationale are listed. Consequently, the resulting key concepts and basic approach are presented.

7.1 ISO/IEC 21000-7: Digital Item Adaptation (DIA)

7.1.1 Goal

To define description tools to enable and enhance the adaptation of Digital Items.

7.1.2 Rationale

As the number of networks, types of terminals and content representation formats increase, interoperability between different systems and different networks is becoming a greater challenge. Common devices such as personal computers, televisions, and mobile devices support a variety of different multimedia content representation formats, and vary in their display capabilities, processing power and memory capacity. Furthermore, the networks that these devices are connected to are often characterized by different capabilities and conditions. Additionally, user preferences and other factors of the usage environment must also be accounted for to enable the delivery of personalized services. Given this complex and dynamic usage environment, it becomes necessary to have a standardized description of the usage environment, as well as a set of standardized tools that enable the scaling of resources and, in general, the adaptation of Digital Items.


The Digital Item Adaptation tools in this specification are clustered into three major categories as illustrated in Figure 5. The categories are clustered according to their functionality and use for Digital Item Adaptation.

The first major category is the Usage Environment Description Tools, which include User characteristics, terminal capabilities, network characteristics and natural environment characteristics. These tools provide descriptive information about these various dimensions of the usage environment, which originate from Users, to accommodate, for example, the adaptation of Digital Items for transmission, storage and consumption.

Digital Item Resource Adaptation Tools comprise the second major category of Digital Item Adaptation tools, which target the adaptation of resources in a Digital Item. In the case of bit stream syntax description, tools are specified to facilitate the scaling of bit streams in a format-independent manner. Such tools are useful for the adaptation of resources contained within a Digital Item at network nodes that are not knowledgeable of the


specific resource representation format. Another tool in this category is terminal and network quality of service. This tool describes the relationship between constraints, feasible adaptation operations satisfying these constraints, and associated qualities. It provides a means to make trade-offs among these parameters so that an adaptation strategy can be formulated. The third tool in this category is referred to as metadata adaptability, which enables the filtering and scaling of XML instances with reduced complexity.

The third set of tools is referred to as Digital Item Declaration Adaptation Tools. In contrast to the set of Digital Item Resource Adaptation Tools, which target the adaptation of resources in a Digital Item, the tools in this category aim to adapt the Digital Item Declaration as a whole. For session mobility, the configuration state information that pertains to the consumption of a Digital Item on one device is transferred to a second device. This enables the Digital Item to be consumed on the second device in an adapted way. Another tool in this set, DID configuration preferences, provides mechanisms to configure the Choices within a Digital Item Declaration according to a User's intention and preference. This enables operations to be performed on elements within the DID, such as sorting and deleting. DIA description messages are intended to provide a means to register, transmit, update and delete DIA descriptions. In this way, Digital Items that contain DIA description instances can be registered and adapted.

Usage Environment Description Tools

• User Characteristics• Terminal Capabilities• Network Characteristics• Natural Environment Characteristics

Digital Item Resource Adaptation Tools

• Bitstream Syntax Description• Terminal and Network QoS• Metadata Adaptability

Digital Item Declaration Adaptation Tools

• Session Mobility• DID Configuration Preferences• DIA Description Messages

Usage Environment Description Tools

• User Characteristics• Terminal Capabilities• Network Characteristics• Natural Environment Characteristics

Digital Item Resource Adaptation Tools

• Bitstream Syntax Description• Terminal and Network QoS• Metadata Adaptability

Digital Item Declaration Adaptation Tools

• Session Mobility• DID Configuration Preferences• DIA Description Messages

Figure 5 — Overview and Organisation of Digital Item Adaptation Tools

7.2 ISO/IEC 21000-10: Digital Item Processing

7.2.1 Goal

To provide tools that allow Users creating Digital Items to provide other Users suggested mechanisms by which they may interact with that Digital Item. This extends to methods for creating, altering, interacting with and consuming elements of the Digital Item.

7.2.2 Rationale

One of the important aspects related to concept of the Digital Item is that the Digital Item Declaration (see Clause 5.2) is a static declaration of only the information (structure, resources and metadata) in the Item; in the declaration itself there is no implied processing of that information. This is important as it contrasts with e.g. HTML based Web pages where the presentation of the information is intermingled with the information itself. While the separation of the information from the usage of the information in Digital Items has significant advantages (different Users can receive very different presentations of information), it also means that on receipt of the static declaration, a User has nothing that indicates how the information should be processed.


7.2.3 Key Concepts

Thus, Digital Item Processing is the area of MPEG-21 that encompasses all the aspects of processing a static Digital Item from a User (and application) perspective. It includes such processing as downloading the Digital Item; requesting IPMP and Rights processing of the DI; downloading and presenting individual media resources; and performing tasks ("methods") that an author requires for a particular DI. While much of Digital Item Processing is still in the early stages of consideration, the last aspect mentioned (Digital Item Methods, DIMs) has been identified of particular importance to Digital Item usage and defined in more detail.

The concept of Digital Item Methods is that, on receipt of a Digital Item, a User will have available a "list" of processes ("methods") that can be applied to the Digital Item. These methods provide a mechanism for a User (author, publisher, distributor, etc) to specify a preferred set of procedures by which the DI should be handled. A simple illustration of this functionality would be a music album DI with an “Add Track” method. The method would allow a User to add a new track to the DI in the preferred format of the DI (i.e., in the correct place in the hierarchy and with the correct descriptors). MPEG intends the methods to be run on a method engine (called the Digital Item Method Engine, DIME), which supports standard base operations (Digital Item Base Operations, or DIBOs; analogous to the standard library of functions of a programming language). Users will be able to create methods for their Digital Items from these base operations and using a standardised syntax (Digital Item Method Language, DIML).

The DIML is based on the third edition of ECMAScript [1]. This provides lexical conventions and syntactical structure, flow control structures (i.e. if/then, while, etc.), primitive data types (String, Boolean and Integer), composite data types (objects and arrays), standard arithmetic, logical and bitwise operators, exception handling, error definitions and support for Regular Expressions.

In the DIP context, the ECMAScript host environment is the MPEG-21 Peer (or more precisely the DIME). DIML extends ECMAScript by defining additional object types, global object properties, and functions that are standardised by MPEG-21 DIP. Additional object types defined in DIML represent such things as a DID document, DIP exceptions, resource status, and the object map. The object map is required to map from DID elements, to objects with semantic significance to a particular DIM (or DIMs). For example, an Item element in a DID can be mapped to a Music Track object, which is understood by an Add Track method.

Additional properties of the global object defined in DIML include a reference to the current DID document object.

Additional functions defined in DIML include the standardized set of DIBOs. MPEG-21 DIP specifies the normative syntax and normative semantics of each DIBO (the “what”), but does not mandate how an MPEG-21 Peer might implement those semantics (the “how”). Any given Peer will be expected to provide some base level of functionality, for example to “play” a resource. The DIBOs provide a standard interface for a DIM author to access this functionality of the Peer. The standardized semantics of the DIBO indicate the generic functionality that must be provided by an implementation of a DIBO. However, the manufacturer of the Peer is free to implement the DIBO to provide that functionality as they wish. The standardized DIML and DIBOs provides for interoperability of DIMs, yet the freedom to implement DIBOs still allows for such things as competition among manufacturers of MPEG-21 Peers, and MPEG-21 Peers suited to specific purposes.

The current set of DIBOs specified can be placed in to one of the following categories.

Operations that manipulate the DID at the XML level, such as inserting or removing elements, setting the value of an element attribute.

Operations that manipulate the state of a DI, such as setting the state of selections within a choice.

Operations that are representations of or associated with an RDD verb, such as play.

Digital Item extension Operations, DixOs extend DIP to allow optimal execution of more complex tasks. The means for invoking a DIxO from DIML is normatively specified, however the actual language used to implement a DIxO is not normative. Currently DIxOs are restricted to being able to call the DIBOs only, and hence a binding for the DIBOs is required for the language in which a DIxO is implemented. In addition an execution environment for the DIxOs implemented in a given language needs to be specified. Currently the


DIP working draft version 2 includes a Java binding for the DIBOs and a specification of a Java execution environment for Java DIxOs, J-DIxOs.

7.3 ISO/IEC 21000-11: Evaluation Methods for Persistent Association Technologies

7.3.1 Goal

To provide an objective and rigorous framework for the assessment of Persistent Association Technologies by setting out a framework for guiding the assessment process. Within that framework, to provide recommendations detailing best practice in undertaking the various aspects of an assessment process, utilising standardised testing methodologies wherever possible.

7.3.2 Rationale

A general task that has been widely addressed with numerous technologies concerns the linking of content items with metadata. By far the most widely deployed approach to date involves juxtaposing metadata and content elements – either within file formats or databases. However, these approaches are “fragile” in so far as the link between content and metadata can easily be deleted or otherwise lost. This has led to the development of families of “Persistent Association Technologies” (PAT) that can provide a degree of resilience in establishing and maintaining the association between content and metadata. Technologies presently fall into two main categories of watermarking and fingerprinting. In recent years there have been some significant cases where PAT has been assessed and/or deployed in commercial applications. In tandem with this, there has been significant debate – especially on engineering issues – and some considerable progress in the techniques used to assess PAT in a variety of application scenarios. In some cases PAT has provided excellent solutions and in other cases results have been less positive.

The rationale of this present document has been to gather the experience and best practice of practitioners who have worked with PAT development, assessment or deployment and to set out this experience for the benefit of others performing similar tasks. Presently, the focus of contributors to this effort has been on PAT for audio applications. However, this document is has been deliberately structured in such a way that future contributions on video or still image technologies could readily be incorporated.

7.3.3 Key concepts

7.3.3.1 Application Framework

Whilst the requirements of PAT and of its assessment in different applications may differ, there are nonetheless many generic factors that can and should be assessed or considered in a structured way. These factors have been set out to form a framework for approaching the assessment task.

7.3.3.2 PAT Parameters

Key parameters of PAT have been identified for assessment, as:

Fingerprint Size;

Watermark Payload;

Granularity;

Perceptibility;

Robustness;

Reliability; and

Computational Performance.


There is a need to consider the performance trade off that occurs as these parameters are varied. The document sets out a description of these factors along with detailed recommendations for assessing them.

7.3.3.3 Issues in PAT

There are issues in PAT, in particular the resistance to malicious attacks, scalability and interactions between different PAT systems. The document provides some information on these issues.

7.3.3.4 Practical Testing

Constructing a practical test environment complete with test items, impairment tools, and automation tools is a considerable engineering exercise. The document sets out advice and guidelines on these topics.

7.4 ISO/IEC 21000-12: Test Bed for MPEG-21 Resource Delivery

7.4.1 Goal

To provide a platform for evaluating standards within the MPEG-21 framework in the context of various resource delivery technologies and scenarios.

7.4.2 Rationale

In order to enable maximum use of its standards WG11 encourages the exploitation of synergies among the different MPEG specifications. ISO/IEC 21000-12 will deliver this synergy beyond MPEG-21 by providing a platform for the integration of MPEG-21 and MPEG-4 specification.

7.4.3 Key Concepts

The Test Bed is designed for assessment of the performance of scalable video codecs in a streaming application and can be extended to a generic environment for the evaluation of resource delivery technologies over unreliable packet-switched networks. In particular, the test bed is designed for the testing and verification of the following technologies in a dynamic environment:

MPEG-21 Digital Item Declaration;

MPEG-21 Digital Item Adaptation;

Scalable video and audio coding technologies;

MPEG-4 delivery using the Internet Protocol and

MPEG IPMP-compilant content protection technologies.

It is important to note that the Test Bed is an informative implementation of how various MPEG technologies which can be integrated into a working system for testing and verification purposes. The specific implementation of MPEG technologies used in the Test Bed represents only one way of achieving this integration and is not part of the normative standards of respective technologies, unless they are part of the reference software of the corresponding MPEG standards.

The Test Bed is mainly composed of three pieces of software:

Server,

Client, and

Network emulator.


A schematic overview of the Test Bed is illustrated in the figure below.

In particular, the network emulator allows the user to specify network parameters such as channel bandwidth, packet loss rate, network buffer size, delay, and jitter, in a network profile and controls the network condition accordingly in real time. The Test Bed employs different audio and video codecs for representing the media content and contains an MPEG-21 Digital Item Adaptation Engine that demonstrates MPEG-21 Network Adaptation QoS mechanisms.

RTSPmux with terminal

capability

Decoder

Mediachannels

(RTP, UDP)

ControlChannel

(RTSP,TCP)

RTSPmux with

SDP

RTSP demux

with SDP

PacketBuffer

Output Buffer

Network Emulator

OfflineMedia

Encoder

TCP

NetworkProfile

Server

User Characteristics

ServerController

StreamBufferNetwork Interface

UDPUDP

NetworkBehavior

control

IPMP

Client

TCP

ClientController

control

RTP/ RTCP

RTP/ RTCP

RTSPdemux

with terminal

capability

Retrans .Monitor

QoSDecision

Streamer

NISTnet

NISTnet

Network Interface

media

Packet Buffer

DIA Engine

QoS DecisionRTSP

mux with terminal

capability

Decoder

Mediachannels

(RTP, UDP)

ControlChannel

(RTSP,TCP)

RTSPmux with

SDP

RTSP demux

with SDP

Output Buffer

Network Emulator

OfflineMedia

Encoder

Offline Media Encoder

TCP

NetworkProfile

Server

User Characteristics

ServerController

MediaDatabase

StreamBufferNetwork Interface

UDPUDP

NetworkBehavior

control

IPMP

Client

TCP

ClientController

control

RTP/ RTCP

RTP/ RTCP

RTSPdemux

with terminal

capability

Retrans .Monitor

QoSDecision

NISTnet

NISTnet

Network Interface

media

Packet Buffer

Digital Item Information(CDI, XDI)

IPMP

Figure 6 — Schematic Overview of the Multimedia Test Bed


Annex A(informative)

List of Activities Related to the Multimedia Framework

This annex gives a non-exhaustive list of activities related to the Multimedia Framework. The activities are grouped into four different categories:

Standardised models and frameworks

Current standardisation activities

Forums and consortia

Specifications produced by forums and consortia

A.1 Standardised Models and Frameworks

A.1.1 CWA (CEN Workshop Agreement) 13699 “Model for Metadata for Multimedia Information”

It defines the terms information resource, metadata and multimedia, comments on the nature of metadata and explores the relationship between metadata and the information to which it refers. A conceptual model for metadata for multimedia information resources was elaborated based on three concepts: metadata classes, roles and actions. Three major roles were identified in the metadata model, creators, service providers and users, who perform actions that apply equally to both information resources and metadata. A life cycle model was described which can be applied either to an information resource or to its associated metadata and illustrates the phases through which an information resource and its associated metadata may pass from creation or acquisition to retention or disposal. The Agreement recommended the development of standardised mechanisms for performing actions on multimedia information resources and metadata.

A.1.2 CWA 13700 “Requirements for metadata for multimedia information”

It presents a requirements taxonomy that identifies a set of basic general requirements. They are classified into a) metadata, and b) facilities needed in association with metadata. The classifications are aligned, respectively, with related concepts in the metadata model (metadata classes) and in the metadata framework (framework decomposition into delivery, access, protocols, discovery and asset management and interoperability). Most of the identified requirements come from several application domains such as Retail, Services, Public Administration, Entertainment, Scientific and Cultural heritage, Publishing, Education and Healthcare. Requirements from two application examples, audio-visual publishing and brokerage, are described in more detail and the taxonomy is used to list requirements in real applications such as the Danish Library use of Dublin Core metadata.

A.1.3 The Metadata for Multimedia Information Framework

It provided a structured classification of information and activities involving metadata for multimedia information in early 1999; providing brief information on a topic, the specifications and standards being developed, what consortia or research projects were actively working in a field and what reference material (books, magazine articles and web sites) were relevant. The framework was never progressed to a CEN Workshop Agreement since it was intended to be a “live” resource with constant updating. Another CEN/ISSS project the “Metadata Observatory” under the auspices of the MMI-DC workshop will now provide web-based information on projects using Dublin Core.


A.1.4 IEC TR 61988 Model and Framework for Standardisation in Multimedia Equipment and Systems

This technical report was compiled by a project team of IEC TC 100; it provided models and frameworks for the standardisation of multimedia technology, being undertaken or to be undertaken by IEC. It covered system interfaces, user interfaces, interchange and distribution, measurement and management and multimedia data and contents. Requirements for physical and logical connectivity, easy operation, safety and security, easy implementation, and environmental safeguards were discussed in the light of a generic model and specific models addressing models of physical and logical connectivity, and inter-system and inter-device models data distribution and management models and information appliance models. Informative annexes discussed possible standardisation requirements in some specific fields such as digital TV broadcasting, internet broadcasting, display systems and games systems.

A.1.5 DAVIC (Digital Audio Visual Council) Framework

DAVIC was formed in 1994 and over five years some 220 organisations from 25 countries representing all sectors of audio and visual manufacturing (computer, consumer electronics and telecommunications equipment) and services (broadcasting, telecommunications and CATV) government agencies and research organisations collaborated to develop specifications of open interfaces and to maximise interoperability across geographical boundaries and between diverse applications, services and industries. The DAVIC specification 1.3.1 was standardised in 1999 as ISO/IEC 16500 (normative) and ISO/IEC 16501 (informative). The specification had a Requirements and Framework section which described digital audio-visual functionalities, system reference models and scenarios. In addition there were architectural guides, technology tool sets and sections on systems integration, implementation and conformance.

A.1.6 IEC ITA OPIMA Specification 1.1

The Open Platform Initiative for Multimedia Access (OPIMA) provides a standardised framework allowing the secure downloading, installation and running of proprietary protection systems (called IPMP systems).

The specification presents an architecture and a description of the function required to implement an OPIMA-compliant system and considers four usage scenarios, portable devices for secure digital music, broadcasting of protected content, wireless access to multimedia content and access to multimedia content on physical data centres. The OPIMA specification is device and content independent. Content includes all multimedia types and executables. The specification is independent of all digital content processing devices and content types. Rules (information that stipulates how content may be used on a given device) determine how business models are established. An IPMP (Intellectual Property Management and Protection) system controls access and use of the content by enforcing the rules associated with it. OPIMA provides a specific Secure Authenticated Channel (SAC) and appropriate interfaces between the IPMP systems and the applications. This communication is enabled by the so-called OPIMA Virtual Machine (OVM), the environment in which the content processing takes place. The IPMP system required to access the content oversees the content processing including decryption (e.g., using DES) and decoding (e.g., using MPEG-4) of content and communicates with the OVM through the IPMP Services API.

A.1.7 ISO/IEC 14496-6 Delivery Multimedia Integration Framework DMIF

Delivery Multimedia Integration Framework allows each delivery technology to be used for its unique characteristics in a way transparent to application developers. DMIF's main purposes are to provide an application interface independent of the networking technology that hides the details of the transport network from the user, and to ensure signalling and transport interoperability between end-systems and managing in real time, QoS sensitive channels. DMIF therefore performs a natural mapping function for an application’s network service requests.

A.1.8 DVB-MHP (Multimedia Home Platform)

DVB-MHP (ETSI TS 101-812) is a series of measures designed to promote the harmonised transition from analogue TV to a digital interactive multimedia future. Based around a series of mandatory Java APIs (Application Programming Interfaces) as well as an optional definition of content and applications format


elements from the HTML family, DVB-MHP promises to provide a domestic platform which will facilitate convergence.

Some 1000 pages long, MHP defines the application lifecycles, security and data download mechanisms for enhanced broadcast, interactive and indeed full Internet. DVB standards are published by ETSI.

Other standards from DVB such as TS 101 224 Home Access Network, TS101 225 In Home Digital Network and TS 101 226 In Home Digital Networks Guide are also relevant to MPEG-21.

A.1.9 IEEE P1520 (includes value added interfaces)

The objective of IEEE P1520 is to enable the development of open signalling, control and management applications as well as higher level multimedia services, through value added service level interfaces, on networks. The scope of the networks considered extends from ATM switches to hybrid switches such as high speed IP switches and routers.

A.2 Current standardisation activities

A.2.1 Mediacom 2004

The project Mediacom 2004 has been established by Study Group 16 in its capacity as lead Study Group for multimedia studies in the ITU-T. The intent of the project is to generate a framework for multimedia communications studies for use within the ITU and other SDOs. The formation of this project has been endorsed by the World Telecommunication Standardisation Assembly 2000.

The project Mediacom 2004 has been established in recognition that:

Gobal standards and harmonized regulations are essential for an effective and democratic Information Society, and consistent multimedia systems and services are part of the core in this Information revolution;

Many standards development organizations (SDOs) and industry forums are developing multimedia standards;

The present convergence trends are bringing further overlaps in standardisation work and, as a consequence, introduce the need for costly and complex gateways to maintain end-to-end interoperability;

The rapid increase in diversity of services and systems increases the possibility of confusion amongst users;

The main objective of Mediacom 2004 is to establish a framework for the harmonised and co-ordinated development of global multimedia communication standards. It is intended that this will be developed with the support of, and for use by, all relevant ITU-T and ITU-R Study Groups, and in close cooperation with other regional and international standards development organisations (SDOs).

The key Framework Standardisation Areas (FSA) identified for study within Mediacom 2004 are as follows:

Multimedia architecture

Multimedia applications and services

Interoperability of multimedia systems and services

Media coding

Quality of service and end-to-end performance in multimedia systems


Security of multimedia systems and services

Accessibility to multimedia systems and services

The Mediacom 2004 project documentation is available at the following website:http://www.itu.int/ITU-T/com16/mediacom2004/index.html

A.2.2 MoU between ISO, IEC, ITU and UN/ECE on electronic business

These organisations have signed an MoU in the field of electronic business to co-operate on standardisation of components involved in the areas of business scenarios, message and interoperability standards for business transactions, and product definition data standards for design, manufacturing and product support.

Each organisation recognises that co-ordinated standards (standards developed within their respective domains) are essential and must be interoperable and technically consistent. Recognising that within electronic business, there is the potential for convergence for all types of data interchange, the work programme will be tailored to bring all types of information exchange development within a single framework. Ongoing activities include:

The BSR project in ISO/TC 154 Processes, data elements and documents in commerce, industry and administration

Development of standards for naming, defining and coding of data elements in ISO/IEC JTC 1/SC 32 Data Management and Interchange , ISO/TC 184/SC 4 Industrial Data-Parts Libraries and in IEC/SC 3D Data sets for libraries of electric component data

Security in EDI transmission (e.g. ISO/TC 68 Banking, securities and other financial services

Maintenance of Open-edi reference model (ISO/IEC 14662)

Technical documentation in ISO/IEC JTC 1/SC 24 Computer graphics and image processing and in IEC/SC 3B

Standards for processing multiple languages, character sets and encoding in ISO/IEC JTC 1/SC 2 Coded character sets

CALS International work on a generic electronic business reference model in a virtual enterprise to support the CALS business scenarios

ITU-T Global Information Infrastructure (GII) Projects

A.2.3 CEN/ISSS

The mission of CEN/ISSS is to provide market players with a comprehensive and integrated range of standard-oriented services and products in order to contribute to the success of the information society in Europe.

A.2.3.1 CEN/ISSS MMI-DC workshop

Recognizing the importance of metadata agreements for the European content industry, CEN started a new CEN/ISSS Workshop on Metadata. A growing number of information services on the Web are using Dublin Core as their basis for descriptions for Web resources. The Dublin Core Metadata Element Set is designed for simple resource description and to provide minimum interoperability between metadata systems. The workshop provides guidance on the use of Dublin Core and is maintaining a metadata observatory.


A.2.3.2 E-commerce workshop

The CEN/ISSS Electronic Commerce Workshop has been established to provide an open and flexible framework for market players (manufacturers, service providers, users, research bodies, administrations, etc.) to identify and progress Electronic Commerce standards and standards-related issues, and to deliver outputs. As Electronic Commerce impacts on all business processes, a common, multi-sectoral approach is crucial for resolving interoperability between technical solutions, which need to be implemented across businesses and value chains. The Workshop offers a coherent and cohesive focus for EC standardization at a European level, within the context of global EC standardization activities.

A.2.3.3 Electronic Signatures (E-SIGN) Workshop

While the EU Directive on Electronic Signatures provides a comprehensive legal framework for the harmonisation of the security infrastructures and authentication services using electronic signatures across Europe, it needs the appropriate technical support that will achieve the full implementation of its legislative prescriptions into the member states laws.

Under the auspices of the EESSI work programme, the E-SIGN WS has been developing a set of deliverables proposing consistent to the Directive and interoperable solutions in a number of key areas: use of trustworthy systems by the Certificate Service Providers (CSPs), development of security-enhanced signature creation interfaces, creation of reliable signature creation devices, elaboration of guidelines on how best to verify a signature with short and long-term validation results, preparation of a set of requirements addressing appropriate conformity assessment mechanisms.

A.2.3.4 ISO TC 46/SC 9

The organisations involved in the administration of identifier systems and projects within ISO TC 46/SC 9 has formed a Joint Initiative to work together on issues relating to the interoperability of their identifier schema. This Joint Initiative is being co-ordinated and assisted by the ISO TC 46/SC 9 Secretariat. The work of this Joint Initiative has been divided into several phases. Phase 1 consists of an analysis of the requirements for identifiers and descriptors in three broadly defined business functions that are central to the content industries: production, distribution, and the management and protection of intellectual property rights. The purpose of this analysis is to establish a shared frame of reference for describing the nature of the business and information transactions that take place in the course of production, distribution, and rights management. It focuses specifically on the requirements of the originators, producers, distributors, registration authorities, and rights administrators involved in the development and delivery of intellectual and artistic content.

Phase 1 of this Joint Initiative is nearing completion. The main deliverable is the document "Content Delivery and Rights Management: Functional Requirements for Identifiers and Descriptors for Use in the Music, Film, Video, Sound Recording, and Publishing Industries".

A.3 Forums and Consortia

A.3.1 WorldWideWeb Consortium W3C

W3C is the organisation that develops primary specifications for the web. XML will form the basis for information interchange between the next generation of computer systems.

XML and pointers to all different XML frameworks e.g., NewsML, ebXML, Open XML , IRML, XBRL/XFRML,CWM (see below).

A.3.2 Multiservice Switching Forum (MSF)

The MSF mission is to accelerate the deployment of open communications systems that realise economic benefits (in the sense of more optimal use), which result from the flexible support of a full range of network services using multiple infrastructure technologies.


A.3.3 Society of Motion Picture and Television Engineers (SMPTE)

The SMPTE 330M-2000 Television - Unique Material Identifier (UMID) standard describes a unique identifier scheme for use in a broadcast environment. The SMPTE 298M standard specifies Universal Labels for the Unique Identification of Digital Data.

SMPTE Metadata dictionary structure is defined in SMPTE 335M while the associated Metadata Dictionary Contents Recommended practice defines a registered set of metadata element descriptions for association with essence or other Metadata, the two specifications must be used together as a pair – neither may be used in isolation.

A.3.4 The European Broadcasting Union (EBU)

The EBU had a PMC P/META (Metadata exchange standards) project (ended in December 2000) with as goals:

To establish understanding between EBU members of the media-related data interchange requirements of media commissioner/publishers (broadcasters), suppliers (producers) and End Users

To validate and extend the Standard Media Exchange Framework (SMEF) model as appropriate against members’ requirements in terms of data and process, noting local synonyms (or translations), to create an “E-SMEF”.

Using E-SMEF, to apply emerging SMPTE metadata standards to the production and broadcast or distribution process, and study the feasibility of creating and adopting common exchange formats for essence and metadata.

To establish understanding of the use of unique identifiers in metadata e.g. the SMPTE UMID, as a crucial linkage tool between unwrapped data (metadata) and wrapped or embedded metadata in media files or streams, and develop protocols for their management between members.

As an aid to commercial and system interoperability between members, and in co-operation with standards bodies in related industries such as music and print publishing, to collate all relevant unique identifier schemes and map them against each other.

A.3.5 TV Anytime Forum

The TV Anytime Forum is an association of organisations that seeks to develop specifications to enable audio-visual and other services based on mass-market high volume digital storage.

The Forum is working to develop open specifications designed to allow Consumer Electronics Manufacturers, Content Creators, Telcos, Broadcasters and Service Providers to exploit high volume digital storage in consumer platforms.

A.3.6 3GPP (Third Generation Partnership Project)

The mission of 3GPP is for the partners to co-operate in the production of globally applicable Technical Specifications and Technical Reports for a 3rd Generation Mobile System based on evolved GSM core networks and the radio access technologies supported by the 3GPP partners.

A.3.7 WAP Forum

The WAP Forum is the industry association that has developed the Wireless Application Protocol (WAP), used for wireless information and telephony services on digital mobile phones and other wireless terminals.

The primary goal of the WAP Forum is to bring together companies from all segments of the wireless industry value chain to ensure product interoperability and growth of wireless market.


A.3.8 Dublin Core

The Dublin Core has become an important part of the emerging infrastructure of the Internet. Many communities are eager to adopt a common core of semantics for resource description, and the Dublin Core has attracted broad ranging international and interdisciplinary support for this purpose. The Dublin Core Initiative has from its beginning been an international consensus-building activity. The Dublin Core Directorate will, in consultation with advisory committees, render judgments as to the character of the consensus and the state of the Dublin Core. The Directorate coordinates Dublin Core workshops, working group activities, and dissemination of information about the Dublin Core initiative via the Web site and other publications. The Dublin Core Directorate is currently hosted by the OCLC Office of Research and Special Projects.

A.3.9 AES

The AES serves its members, the industry and the public by stimulating and facilitating advances in the constantly changing field of audio. It encourages and disseminates new developments through annual technical meetings and exhibitions of professional equipment, and through the Journal of the Audio Engineering Society, the professional archival publication in the audio industry.

A.3.10 IRTF Internet DRM WG

IDRM is an IRTF (Internet Research Task Force) Research Group formed to research issue and technologies relating to Digital Rights Management (DRM) on the Internet (http://www.idrm.org). The IRTF is a sister organization of the Internet Engineering Task Force (IETF).

A.3.11 OpenEBook Forum

The Open eBook Forum (OeBF) is an association of hardware and software companies, publishers, authors and users of electronic books and related organisations whose goals are to establish common specifications for electronic book systems, applications and products. OeBF will benefit creators of content, makers of reading systems and, most importantly, consumers, helping to catalyse the adoption of electronic books. OeBF will encourage the broad acceptance of these specifications on a world-wide basis among members of the Forum, related industries and the public and it will increase awareness and acceptance of the emerging electronic publishing industry.

A.3.12 cIDf (Content ID Forum)

cIDf is a forum to standardize "Content ID", which is a set of well-defined metadata including a unique code embedded in each digital content item, guarantees content uniqueness and stabilizes content value. It creates an environment for open-type content distribution that encourages active usage such as the creation of derivative products.

A.4 Specifications produced by forums and consortia

A.4.1 Common Warehouse Metamodel (CWM) Specification, published by OMG

It addresses the problem of metadata management and specifically reconciliation of inconsistent metadata when data from different sources are merged. In addition, CWM standardises the syntax and semantics needed for import, export, and other dynamic data warehousing operations. The CWM specification extends to APIs interchange formats, and services that support the entire lifecycle of metadata management.

A.4.2 Biztalk Framework

The Microsoft BizTalk Framework is an Extensible Markup Language (XML) framework for application integration and electronic commerce. It includes a set of guidelines for how to publish schemas in XML and how to use XML messages to easily integrate software programs together in order to build rich new solutions.


Microsoft Corp., other software companies and industry standards bodies will use the BizTalk Framework to produce XML schemas in a consistent manner.

A.4.3 RosettaNet

RosettaNet specifies standard electronic business interfaces for the business-to-business exchange of technical information for Electronic Components enabling for secure electronic communications between foundries and their customers, suppliers and marketing partners. The immediate focus for establishing a uniform electronic system for the foundry industry includes: online order entry, tracking work in progress, engineering reports, project status, delivery status, forecasting and planning, and payment.


Bibliography

[1] ECMA. ECMAScript Language Specification. 3rd Edition. Available from http://www.ecma-international.org/publications/files/ecma-st/Ecma-262.pdf

[2] IETF RFC 791 (also STD 5), Internet Protocol (IP).

[3] IETF RFC 793 (also STD 7), Transmission Control Protocol (TCP).

[4] IMPRIMATUR Services Ltd: Synthesis of the IMPRIMATUR Business Model

[5] ISO/IEC 10918, Information technology – Digital Compression and Coding of Continuous-Tone Still Images (JPEG).

[6] ISO/IEC 11172, Information technology – Coding of moving pictures and associated audio for digital storage media at up to about 1.5 Mbit/s (MPEG-1).

[7] ISO/IEC 13818, Information technology – Generic coding of moving pictures and audio (MPEG-2).

[8] ISO/IEC 14495, Lossless and Near-Lossless Compression Of Continuous-Tone Still Images (JPEG-LS).

[9] ISO/IEC 14496, Information technology –Coding of audio-visual objects (MPEG-4).

[10] ISO/IEC 14772, Information technology -- Computer graphics and image processing – The Virtual Reality Modelling Language (VRML).

[11] ISO/IEC 15444, Information technology – JPEG 2000 image coding system (JPEG-2000).

[12] ISO/IEC 15938, Information technology – Multimedia content description interface (MPEG-7).

[13] ISO/IEC 8879, Information processing -- Text and office systems -- Standard Generalised Mark-up Language (SGML).

[14] ISO/IEC Directives, Part 3: Rules for the structure and drafting of International Standards, 1997.

[15] ISO/IEC JTC 1/SC 29/WG 11/N 3162 Maui, October 1999: CWA Model for Metadata for Multimedia Information.

[16] ISO/IEC TR 10000-1: Information technology — Framework and taxonomy of International Standardised Profiles — Part 1: General principles and documentation framework.

[17] ITU-T G.723, Dual rate speech coder for multimedia communications transmitting at 5.3 and 6.3 kbit/s (G.723).

[18] ITU-T G.728, Coding of speech at 16 kbit/s using low-delay code excited linear prediction (G.728).

[19] ITU-T H.245, Control protocol for multimedia communication (H.245).

[20] ITU-T H.261, Video Codec For Audiovisual Services At p x 64 Kbits (H.261).

[21] ITU-T H.263, Video coding for low bit rate communication (H.263).

[22]Leonardo Chiariglione: Technologies for E-Content, August 1999, published on the Internet at www.cselt.it/leonardo/paper/wipo99/index.htm.

[23]W3C XML-C14N, eXtensible Mark-up Language (XML).


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